This invention relates generally to the fabrication of integrated circuits.
In the fabrication of integrated circuits, it is common to form junctions for transistors by ion implantation. For example, using a gate structure as a mask, an ion implantation may form implanted regions. As a result of the ion implantation, damage may occur to the semiconductor substrate. In addition, many of the implanted species may not find substitutional sites.
In order to repair the damage and to activate the species into substitutional sites, it is common to use an annealing or heating step. In modern semiconductor processes rapid thermal annealing may be utilized to apply a high heat in a relatively short amount of time.
Another option is to use laser energy, such as an infrared laser, to rapidly heat the implanted region. Existing efforts to use laser energy have run into difficulties because the laser energy may be so intense it actually melts the gate structures that are already in place on the substrate at the time of the annealing step.
Thus, there is a need for better ways to anneal implanted regions in the manufacture of integrated circuits.